what do you mean, the color variation or the shape? If you're talking about the shape, it's a cloth simulation with a near zero cloth density. I mean, the cloth is almost weightless. Then it's just a matter of moving the cloth in the approximate direction I want and the simulator does the rest.
I meant the shape ^^ Ah, I thought maybe it was a morphable prop, but I'm no good at morphing those things with a million little sections O.o I don't deal with the cloth room too much, but thanks for the tip